Rail shipments of crude oil rose to 119,634 carloads in the most recent fiscal quarter, an increase of more than 10 percent over the 106,605 shipments in the comparable period last year, according to figures released Thursday by the American Association of Railroads.

The association, an industry trade group, called it the busiest quarter ever for crude oil shipments by rail. In the single month of August, shipments rose 25 percent compared to the previous August. Shipments of other commodities showed more modest gains.

As oil production has soared past pipeline capacity, trains have become a favored alternative for the petroleum industry. But as traffic continues to increase, the practice has drawn intense scrutiny.

A series of accidents and spills, including a derailment that killed dozens of people last year in a small town in Canada, have prompted federal officials to issue safety warnings and emergency orders.

As smaller accidents strike communities across the country, fire officials say they fear a major catastrophe. The U.S. Department of Transportation has proposed new regulations on rail worker training, oil composition testing, train speed and tank car construction.

Rail officials say they can manage the shipments on their own with careful route selection, speed control and inspections.